Cooling apparatus



p 8,- 1937. R. WOLFERT 2,094,565

c'oommz APPARATUS Filed Aug. 14. 1934 WITNESS ES: INVENTOR W EownRoRMoL aRT.

BY ATTOR Y Patented '28, 1937 UNITED STATES COOLING APPARATUS Edward Wolfert, Wilkinsburg, Pa., assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 14, .1934, Serial No. 739,729

Claims.

My invention relates to cooling or refrigerating apparatus, more particularly to-refrigeratin'g apparatus having a plurality of evaporator passages, and it has for an object to provide im- 5 proved operation thereof.

A further object is to improve the distribution of liquid refrigerant to the several eyaporator passages. v

Another object is to increase the cooling eiTect of the evaporator passages. 1

In refrigerating apparatus of the mechanical compression type, as the pressure of the refrigerant is reduced for admission into the evaporator, a portion of the refrigerant is vaporized, thereby providing a mixture of liquid and vaporous refrigerant. Where .an evaporator is employed having a plurality of passages arranged in parallel with respect to flow of refrigerant, difiiculty is encountered in distributing the refrigerant to the evaporator passages in such manner that the several passages shall receive liquid and vaporous refrigerant in the same pro,- portions. Also, the vaporous refrigerant has done most of its work-in cooling the liquid refrigerant.

In accordance with my invention, I provide a separator between the expansion valve'or other pressure-reducing means and the means for distributing refrigerant :tothe several evaporator passages. The vaporous refrigerant is separated and preferably returned to the-inlet of the com pressor, only liquid refrigerant being conveyed to the distributing means.

The above and other objects are effected by lowing. description and claims taken in connection with the accompanying drawing, forming a part of this application, in which:

The singlefigure is a diagrammatic view of a0 apparatus embodying my invention.

- evaporator!!! comprising a plurality of coils H, whicharearranged in parallel with respect to flow of refrigerant; The fluid to be cooled is circulated in heat exchange "relation. with the [-coils, for example,'air for an enclosure to be cooled may be conveyed by suitable means in contact with the several coils, flowing over the several coils in parallel or in series. The coils II are/ preferably provided with transversely-extending flns Ii to increase the air cooling sur- 'face. Capillary or flow-resistance tubes l2 are provided for distributing the refrigerant to the several coils. When the fluid to be cooled flows over the coils in parallel, these tubes are identica my invention as will be'apparent from the fol-.

Referring to-the drawing in detail, I show an and distribute refrigerant in equal quantities, while if the fluid to be cooled flows over the coil successively, the tubes H are proportioned toadmit refrigerant in successively decreasing quantities in accordance with the respective capacities of the several coils.

The refrigerating or condensing unit, for supplying liquid refrigerant to the evaporator l0, is indicated generally by the reference numeral I3. It comprises a compressor I4 whose inlet is connected to the outlet l5 of the evaporator III by a suction conduit "5. The outlet of the compressor is connected by a conduit H to a condenser 18. The latter is cooled in any suit-. able manner, for example, a fan I9, driven by a motor 20 may be provided for circulating air over the condenser for cooling the same. The outlet of the condenser is connected through a conduit I19 withan expansion valve 2!. The latter is preferably of thetype known in the art as a thermostatic expansion valve, having a thermostatic bulb 22- responsive to the temperature of the refrigerant discharged from the evaporator through'the suction conduit [6 and connected to the valve by a tube 23. This type of expansion valve regulates the flow of, refrigerant so as to a mit such quantity of liquid refrigerant to the evaporator as will be completely evaporated therein. It. is to be understood, however, that any other device for reducing the pressure'of the refrigerant may be employed.

The outlet of the expansion valve is connected throughja conduit 24 to a separating chamber '25. fThe lower portion of this chamber is connected through a conduit 26 and a connection or fitting 21 to the inlet ends of the capillary tubes l2. The-upper portion of the separating chamber 25 is connected through a conduit 28 to the suction conduit IS. A float valve 29 may beprovided in the separating chamber 25 to restrict the escape of vaporous refrigerant to the conduit 28 if the level of .liquid refrigerant rises in the chamber.

The operation of the above-described apparatus is'as follows: vaporized refrigerant is withdrawn from the evaporator by the compressor l4 and the compressed refrigerant discharged through conduit IT to the condenser 18. It is condensed therein and conveyed through conduit l9 to the expansion valve 2| in which its pressure is reduced. As the pressure of the refrigerant is reduced, the boiling point or saturation temperature thereof is reduced below the temperature of the refrigerant, so that a portion of the refrigerant is vaporized in reducing The mixture of vaporous and liquid refrigerant flows through the conduit 24 into the separating chamber 25, the liquid refrigerant collecting in the bottom portion of the chamber and the vaporous refrigerant collecting in the upper por tion of the chamber. The vaporous refrigerant flows through the conduit 28 to the suction conduit l6 through which it is returned to the compressor to be again compressed and recirculated, this portion of the refrigerant having effected substantially its share of cooling work in reducing the temperature 'of the liquid refrigerant.

The vaporous refrigerant having been separated, only liquid refrigerant flows through the conduit 26; and the connection 21 to the capillary 'tubes. Inasmuch as the fluid flowing into the several tubes is identical, said tubes distribute the refrigerant at all times in proportion to their flow capacities which, as stated above,

may be identical or in successively-decreasing proportions, or which may be in any other desired proportions. As the liquid refrigerant flows through the several coils, it is vaporized by the extraction of the heat from the fluid being cooled and the vaporized refrigerant is discharged through the outlet ii to the suction conduit IE to be recirculated.

If desired, the float valve 29 may be provided in the chamber 25. As the level of liquid in the chamber tends to rise, the float valve reduces the flow of vaporous refrigerant into the conduit 28, thereby maintaining a substantially constant level of liquid in the chamber 25 and preventing the possibility of liquid refrigerant escapingthrough the conduit 28.

From the above description, it will be seen that I have provided an arrangement whereby refrigerant fluid of uniform character is supplied to the distributing means, so, that refrigerant is supplied to the several evaporator coils or passagesvat all times in-desired proportions. A further advantage of the above arrangement is that only liquid refrigerant which has capacity to absorb latent heat is admitted to the several coils, thereby increasing their effectiveness per unit area of cooling surface, the vaporized refrigerant which has done its work in cooling the liquid refrigerant by-passing the distributing means and the evaporator passages.

While I have shown iny invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. In refrigerating apparatus, the combination of a plurality of evaporator passages, means for compressing and condensing the vaporized refrigerant discharged from said evaporator passages, means for reducing the pressure of the liquid refrigerant from the last-mentioned means, means for distributing liquid refrigerant from the pressure-reducing means to the several evaporator passages, and for regulating the flow thereof in accordance with the quantityof liquid refrigerant that can be completely vaporized in the evaporator passages and means for separating the vaporized refrigerant between the pressure-reducing means and the distributing means and for mixing the same with the vap r- 9,094,565 the temperature of the remaining liquid portion.

ized refrigerant discharged from the evaporator passages before the latter is compressed.

2. In refrigerating apparatus, the combination of an evaporator, means for withdraying vaporized refrigerant from said evaporator and providing a supply of liquid refrigerant, means for at least partially reducing the pressure of said liquid refrigerant thereby effecting partial vaporization thereof, a separating chamber communicating directly with said pressure reducing means so that substantially all of the liquid refrigerant leaving said pressure reducing means is delivered to said separating chamber in liquid state, means communicating with said separating chamber adjacent the bottom thereof for conveying liquid refrigerant from said separating chamber to the-evaporator, means communicating with said separating chamber adjacent the top therefor for discharging vaporous refrigerant from the separating chamber, and means responsive to the liquid level within the separating chamber for controlling the discharge of vaporous refrigerant therefrom.

3. In refrigerating apparatus, the combination of a plurality of evaporator passages arranged in parallel with respect to flow of refrigerant, means for withdrawing vaporized refrigerant from said evaporator passages and providing a supply of liquid refrigerant, means for at least partially reducing the pressure of said liquid refrigerant thereby effecting partial vaporization thereof and for regulating the flow thereof in accordance with the quantity of liquid refrigerant that can be completely vaporized in the evaporator passages, means for distributing liquid refrigerant from the last-mentioned means to the several evaporator passages, and means for separating the vaporized refrigerant between the pressurereducing means and the distributing means.

4. In refrigerating apparatus, the combination of a plurality of evaporator passages arranged in parallel with respect to flow of refrigerant, means for withdrawing vaporized refrigerant from said evaporator passages and providing a supply of liquid refrigerant, means for at least partially reducing the pressure of said liquid refrigerant thereby effecting partial vaporization thereof and for regulating the flow thereof in accordance with the quantity of liquid refrigerant that can be completely vaporized in the evaporator passages, means for distributing liquid re-.

frigerant from the last-mentioned means to the several evaporator passages, and means for separating the vaporized refrigerant between the pressure-reducing means and the distributing means and returning the same to the first-mentioned means.

5. In refrigerating apparatus, the combination of means for supplying liquid refrigerant under pressure, expansion valve means for reducing the pressure of the refrigerant, an evaporator comprising a plurality of passages, means for distributing refrigerant to the several evaporator passages, a separator between the expansion valve means and the distributing means for separating the gaseous refrigerant from the liquid refrigerant, and means responsive to level of liquid refrigerant in the separator for controlling the discharge of gaseous refrigerant therefrom. 6. In refrigerating apparatus, the combination of a plurality of evapoi'ator passages, means for withdrawing vaporized refrigerant from said evaporator passages and providing a supply of liquid refrigerant, means for at least partially reducing the pressure of said liquid refrigerant thereby effecting partial vaporization thereof. flow resistance tubes for distributing refrigerant to the several evaporator passages, and means i for separating vaporized refrigerant between the pressure reducing means andthe flow-resistance tubes, whereby only liquid refrigerant is delivered to the latter.

the several passages of the evaporator, expansion valve means for at least partially expanding the refrigerant before admission to the flow-resistance tubes, and means for separating vaporized refrigerant between the expansion valve means and'the flow-resistance tubes and for conveying said vaporized refrigerant to the inlet of the compressor, said vapor by-passing the flow-resist- I ance tubes and the evaporator.

8. In refrigerating apparatus, the combination I of a plurality of evaporator passages, means for compressing and condensing the vaporized re-' frigerant discharged from said evaporator passages, means fprreducing the pressure of the condensed refrigerant thereby effecting partial vaporization thereof and for regulating the flow thereof in accordance with the quantity of liquid refrigerant that can be completely vapor ized in the evaporator passages, a separating chamber receiving the liquid and vaporous refrigerant from said pressure-reducing means, a plurality of flow-resistance passages for distributing liquid refrigerant from the lower portion of said separating chamber to said evaporator passages, and means for removing vaporous refrigerant from the arating chamber and mixing the same with the vaporized refrigerant discharged from the evap orator passages before the latter is compressed.

9. In refrigerating apparatus, the combina-' tion of a. plurality of evaporator passages for carrying a common cooling load, means for reupper portion of said sep a 3 moving vaporized refrigerant from said passages at substantially the same pressure and compressing the same, means for condensing the compressed refrigerant, means for reducing the pressure of the condensed refrigerant and control- 5 ling the flow thereoL-means for separating the vaporized and the liquid refrigerant discharged from said pressure reducing means and mixing the former with the vaporized refrigerant discharged from said evaporator passages before the latter is compressed, means for distributing liquid refrigerant in predetermined proportions to said evaporator passages comprising passages of constant flow resistance, and means providing only liquid refrigerant from said separating means to said distributing means at the point at which the liquid refrigerant is divided among said evaporator passages.

10. In refrigerating apparatus, the combina tion of a plurality of .evaporator'passages for carrying a commoncooling load, means for removing vaporized refrigerant from said passages at substantially the same pressure and compressing the same, means for condensing the compressed refrigerant, means for reducing the pressure of the condensed refrigerant and regulating the flow thereof 'in response to an operating condition of said evaporator passages so that all of the liquid refrigerant supplied thereto isvaporized before being discharged therefrom, means for separating the vaporized and the liquid refrigerant discharged from. said pressure reducing means and mixing the former with the vaporized refrigerant discharged from said evaporator passages before the latter is compressed, means for distributing liquid refrigerant in predetermined-proportions to said evaporator passages comprising restricted distributor passages of fixed flow resistance communicating with the respective evaporator passages, and means pro- 40 viding only liquid refrigerant from said separating means to said distributing meansv at the point at which the liquid refrigerant is divided among said distributor passages.

EDWARD R. 

